Project BlownZ’s Winter Chassis Build-Up At PMR Race Cars

Our Power Automedia team had a breakout year in 2013 with Dragzine’s Project BlownZ Chevrolet Camaro, as we crept up on the performance race after race and finally put it all together for our first win at the season’s final event, taking home the NMCA WEST 275 radial hardware in Bakersfield and surpassing the class’ elapsed time record in the process. But this is heads-up drag racing, and if you stop advancing our program for even a second, the competition will leave you squarely in the dust.

With visions of the NMCA WEST championship dancing in our minds, and plans to travel east to take on the heavy hitters in X275 and Street Outlaw later in the year, there was no question we’d have to go all-in with BlownZ if we wanted to be competitive this season. As they say, go big or go home, right?

So just like that, our perfectly good race car was in the Power Automedia garage, being stripped down to nothing but the bare Camaro shell. Awaiting it was the team at PMR Race Cars — Tony, Phil, and Charles — who were tasked with turning around a brawny fighter and building a brand new car in less than eight weeks. Along the way they’d be assisting us in documenting the build-up for the very article you’re reading here.

We’ve already given you some sneak peeks at other parts of the project, including the header and bullhorn fabrication, the intercooler plumbing, the new lightweight Carbon Racetech seat. But this is the mothership, where we’ll wrap the entire build up. Along the way, we’ll also be taking a look at a number of components that we sourced from the folks at Quarter-Max and Rick Jones Race Cars to help make the build a reality.

And we begin with, well, a bare race car.

Getting Underway

Here’s BlownZ being stripped down in preparation for the crew at PMR Race Cars.

As we disassembled BlownZ, one our goals for the project going forward was the further reduction of weight, anywhere we could find an area to remove some. We’d accomplished a lot in this department last season, adding fiberglass doors and polycarbonate windows, and cutting our power usage so as to utilize just a single battery rather than two, among other small changes that got us under the 3,600 lb. race minimum, without ballast. So as we reached the point of a bare shell in the shop, we began removing some of the unnecessary steel that remained in the car, including the core support and other sheet metal and parts and pieces that were unneeded, either for function or to meet the class rules.

Mocking up the wheels and tires for fitment is critical at this stage. This photo shows actual ride height and placement of the tire in the wheel well. We’ll be using Tim McAmis Race Cars’ 34-inch mini-tubs in this build, which are specifically designed for drag radials.

Once at PMR Race Cars, an hour up the road from our offices, Tony, Phil, Charles, and the crew immediately got to work on BlownZ, mocking it up on the jig at the specified new ride height, which we should say is LOW. One of the first orders of business on the checklist was fitment of the new Racecraft Inc. rear end housing that we’d purchased for the build. Although much of the 25.5 roll cage had been removed, we left the stock rear framerails in the car to help PMR align the housing and take all the measurements they’d need. As you’ll see later, the framerails will be removed to be cleaned, dipped, and sectioned before being put back in the car.

Our planned ride height, measured from the pinch weld of the body to the floor, was 4-1/4-inches, which is plenty low for a car of this style to transfer weight properly.

In short order, the main hoop for the new roll cage was going into the car. As well, PMR got to work fabricating the main “#1” bar, which would span the width of the car and incorporate itself into the roll cage while also serving as the primary mounting point for the rear lower control arms. This bar is set up in the exact stock location, but gives more freedom of upward and downward adjustability of the front suspension mounting point.

A critical step at this stage of the process is mocking up the wheels and tires for proper fitment, because we certainly don’t want to move forward with the chassis, only to find a problem later. We’ll be using a set of 34-inch carbon fiber mini-tubs from Tim McAmis Performance Parts later on to contain the Mickey Thompson 275 radials.

PMR mocked up the main hoop and got some of the initial bends in place. You can see the rear framerails have been temporarily removed to make way for the 25.3 chassis build.

Moving on with the chassis and suspension preparations, PMR worked to engineer the 46-inch front mount torque arm from Racecraft into the 25.3 floor x-brace, which will offer plenty of adjustability for our tuning needs later. The x-brace portion of the chassis, required to meet the 25.3 certification, is in the car at this stage. The frame rails tie directly into the front and rear frame rails of the stock Camaro chassis, and the x-brace itself ties into the torque arm. The rear control arm mounting locations then tie into the stock frame, stock framerails in the rear, and the 25.3 framerails, along with the “#1” bar. When complete, the framerails will go below the floorpan, and the “#1” bar and rocker bars will go above it.

Making Progress

At this point, we’ve got part of the 25.5 roll cage cut out, but we’ve still got the rear framerails in the car to check fitment on the Racecraft rear end housing and take all of the measurements that we need. The framerails will come out soon just to be cleaned, dipped, and sectioned, but they will be put back in soon.

(Left) This mock-up shot gives you a better idea of how this is engineered. To the right of the control arm mount is where the stock framerail will be once the rear framerails come back and get re-welded into the car. We left the stock framerail ‘stub’ in so we could get a precise location on the lower arms and for the re-welded rear rails. You’ll also see our stock floorpans are out of the car. PMR cut them out and will re-weld them back into the car once the 25.3 is complete. (Right) Here you can see the front framerails and how our 25.3 frame rails will intersect into the front frame. You can see the stock firewall in this picture. We're required to keep the stock firewall complete and intact.

PMR’s lead fabricator, Charles, was soon finished with the front portion of the new roll cage, including the A-pillar bars and the top of the front hoop. For both safety and quality, the bars were all tucked up into the roofline as tightly as possible. An “X” in the roof structure is also part of the requirements for 25.3. With the main hoop in place, Charles began construction of the Funny Car cage that will surround the seat. And speaking of the seat, the PMR team took his opportunity to mock the new Racetech seat up for fitment before moving forward with the finished cage. At this stage, the cage was only an estimated 40 percent complete.

This is our new PMR main “#1″ bar which spans the width of the car and is incorporated both into the 25.3 chassis/cage but also serves as the primary mounting points for our rear lower control arms. This is setup in the exact stock location but allows upward and downward adjustability of the front suspension mounting point. It’s also tied into the cage and 25.3 frame rails so that it will transfer all of the power from our engine properly into the chassis.

While all of that was going on, the OEM framerails returned from dip-strip and were re-welded into the factory location. Upon their reinstallation, the framerails had to be mildly clearanced to fit the tires and the rear end housing (vertically).

(Left) The x-brace in the rear tree/rear down bars. Our Anti-roll bar, wishbone, and shock mounts will depend on this critical bar. (Right) This provides a nice bird’s eye view of the OEM F-body rear frame rails and how our rear tree rails run next to each other.

There’s quite a bit of work and welding to be done at this stage before the floorpan can go into the car. Namely, the completion of the entire back half of the new 25.3 chassis. PMR engineered a rear tree like you’d find on any modern-day Outlaw Radial or X275 car for BlownZ. This is an integral part of any race car, because it handles so much of the stress and torsional forces that are placed upon the chassis. The lower tree rails, as you can see in the photos, run right in parallel with the OEM F-body rear framerails. A pair of down bars were than bent and welded from the top hoop to meet the rear tree, as outlined in the 25.3 specifications. Likewise, as part of the rules, an x-brace was fabbed up to create structural support between the two rear tree down bars, with triangulation of the rear tree incorporated throughout. The down bars are where the anti-roll bar, wishbone, and shock mounts will mount to, so beyond simple safety, you can imagine why this area of the car needs to be strong and rigid. Avoiding twist in the chassis is absolutely paramount.

To The Front

Racecraft’s newly redesigned 4th Gen F-Body k-member just arrived from chilly Minnesota. This k-member is chrome-moly and is designed for the lightweight Stiletto rack.

Our trusty frame rails are back from the stripper. PMR is set up to reinstall the frame rails next week.

With work progressing right along out back and in the interior of the car, the PMR team shifted to the front end where, among other things, we have a trick new bolt-in K-member from Racecraft on-hand to bolt up to the chassis. This K-member is a newly-designed piece for the fourth-gen F-bodies, made from chromoly tubing and designed for lightweight stiletto steering racks.

(Left) Work continuing on the front of the car. This gives a nice shot of the Racecraft bolt-in K-member as the car sits up on the chassis jig at PMR. (right) The LSX money maker. PMR is mounting the newly-built engine and working on the crankshaft centerline for optimum weight distribution.

There was still much work to be done at this stage, but that didn’t keep us from gaining a little preview of what the finished product will look like, as we dropped in the brand new money-maker, our 400 cubic inch LSX powerplant built by Late Model Engines in Texas, for fitment and mocking-up of the motor mounts and motor mount tabs, while positioning and measuring the crankshaft centerline in the process for optimum weight distribution. With the engine in place, the team could also test fit the height of the new 123mm throttle body with a four-inch single barrel intake from Wilson Manifolds atop the motor, of which the five-inch tubing will be routed through the firewall to the intercooler and back.

Over The Hump

Here you can see the engineering PMR is putting into the chassis build. The framerails (as part of the 25.3) actually tie directly into the front and rear frame rails of the stock Camaro chassis. The x-brace – also 25.3 required – ties into the torque arm. The rear control arm mounting locations tie into the stock frame, stock frame rails in rear, and to the 25.3 frame rails and #1 bar. It’s a tightly integrated package. You can see better now how the floorpan is going to reinstalled. The frame rails will go below the floorpan, the #1 bar and the rocker bars will go above.

Things really kicked into gear in early February, with plans to begin testing in just over a month before the NMCA WEST season opener in late March. The PMR team was hard at it to complete the Funny Car cage and the rest of the center portion the chassis, while completing the triangulation and x-brace bars out back. The engine, having been situated for mock-up purposes was pulled back out, so that the upper tower support bars of the chassis could be fitted, cut, and welded, and the new sheet metal firewall (situated in front of the OEM firewall) could also be fabricated and welded in place.

Taking the weight of the car and the speeds we’re planning to attain into account, we knew it was time to transition from a single parachute to a set of dual chutes in the rear. For this, we turned to Quarter-Max and their Dual Parachute Mount Kit, which accepts any brand of parachute — in our case we used a set of Stroud’s 430-30 Series Pro-Mod chutes. This kit is constructed of 3/8-inch chromoly, and is designed to deploy the parachutes in separate directions for a lesser chance of entanglement. As part of the kit, Quarter-Max supplies the tubing to mount the bracket to the chassis, as PMR has done by welding it to the rear of the chassis.

PMR did final mock up on the 400-inch LME LSX Engine with fitment on the front frame rails, motor plates, and other key areas. We needed to get an idea of where to trim the new Optic Armor window and what we needed to do for the induction trimming since the supercharger tubing would have to run straight in to the engine through the firewall.

The PMR team did a final engine mock-up once the front half of the chassis was mostly done (leaving essentially the ‘tree’ yet to be fabricated. This was done both to check the motor mounts and other fitment and clearances, but also to give us an idea of where to trim the new windshield for our supercharger and intercooler tubing to route the through the firewall. We teamed with our friends at Optic Armor Performance Windows, who supplied us with one of their drop-in, blackout (or DIBO, as they call it), polycarbonate windshields. Optic Armor’s design and construction of their windows provides a virtually scratch-proof surface that has unparalleled strength, and will be right at home on BlownZ.

(Left) We worked with the team at Quarter-Max Racing Components to outfit us with some of their very trick bits and pieces. We're going to be upgrading to dual Stroud parachutes this year – and so we used the Quarter-Max Dual Parachute Mount Kit (Part No. 209104-1) to get that done, with PMR handling the fabrication. The QM Dual Chute Mounts will accept any brand of parachute and offered pre-welded pack mounts. (Right) We left the OEM firewall in place and decided to do a sheet metal overlay to make it look clean. This will also address the strange overhang in the F-Body since our new firewall overlay will go straight up to meet the window.

As pointed out earlier, a new firewall was fabricated of sheet metal that overlays the less-than-pretty OEM firewall (or what was left of it), which was done to address the overhang in the F-body and will allow the firewall to extend straight up to meet the window.

Nearing The Finish Line

At this point, BlownZ was really looking like a race car again. The crew at PMR began mocking up the F1X-12A supercharger, in terms of where the supercharger itself will be positioned in front of the motor, and how the five-inch tubing will route itself around the engine and shock tower and back to the firewall. At the same time, the front tree began taking shape, as did the new floorpans inside the car. With the floor tacked in for mocking purposes and the engine in position, a dummy transmission was also bolted in place for measurement of the removable transmission tunnel that would soon be fabricated to house our new Hughes Performance three-speed Turbo 400. While we won’t be removing the transmission at any point from inside the car, the tunnel does give us access to quick transmission and converter maintenance at the track.

(Left) PMR started the rear tub process by mocking up a cardboard rear tub. We're using 34-inch “mini-tubs” that Tim McAmis sells specifically for the 275 Pro and 315 Drag Radial racers. They are about 75% of the size of a regular wheel tub. (Right) Both tubs are installed, but have not had final rivets installed. This also shows the rear sheet metal work. The factory framerails are intact (you can’t see them in this shot because they tuck next to the wheel tubs), but in reality, we have built a second set of framerails which are what the chassis relies on for integrity.

With the rear tree complete, work turned to the new 34-inch carbon fiber wheel tubs designed specifically for 275/315 radial tires that we sourced from Tim McAmis Performance Parts, which will be highlighted in detail in an upcoming tech story. The PMR crew mocked up the tub fitment, as you might have guessed, using cardboard. That layout was then transferred from the cardboard to the actual tub and positioned in the car up against the factory frame rails and riveted into place.

Kooks Custom Headers hooked us up with a complete Stainless Steel bullhorn header kit that Greg Holman at REF used to build our headers. The Kooks kit from Chris, Jr. and the race experts in NC comes with pretty much everything you need to build the system – from the collector to the 2-1/4 and 2-1/8 tubing and flanges. We will have a complete gallery and story on the header assembly but this is a cool shot of the final product (all except the bullhorn itself). The muffler and bullhorn is 4.5-inches.

Quarter-Max To The Rescue

A number of components from the folks at Quarter-Max and Rick Jones Race Cars went into this build, in addition to the aforementioned parachute mount kit. Quarter-Max produces a whole catalog full of hardcore racing parts to save chassis builders and do-it-yourselfers the time involved in fabricating the many small pieces that make up a race car, and they came in quite handy in speeding along our build.

Quarter-Max’s Pro Series brake pedal, which fits on a one-inch diameter shaft and comes with all of the hardware needed for installation.

“All our parts are race-proven, developed, and tested here at our facility, and with our own CNC and water jet machines, much of what comprises the Quarter-Max catalog is produced in-house,” said Quarter-Max’s Josh Dixon. “Rick [Jones] is continually striving to develop new parts and expand on things that he’s gotten inspiration for, and by having much of it in-house, we’re able to maintain tight control of the quality of the products that we sell. We feel that this really gives us an advantage in this industry.”

Quarter-Max boasts a lineup of more than 4,000 different parts covering every facet of a race car’s construction, and as a dealer for many of the top manufacturers in the industry, it includes hundreds of quality, name-brand parts in addition to all of their in-house components.

Continued Dixon, “In the beginning we were offering a lot of pre-welded kits that were more dedicated to the Rick Jones-built cars, but today, we focus on producing components that are more universal, to really reach the do-it-yourself racers.”

Also inside the cockpit is Quarter-Max’s Pro Series steering column kit, made of 4130 chromoly.

PMR utilized the Pro Series Steering Column kit from Quarter-Max (Part No. 203101), which is designed to mount easily in nearly any race car chassis. The shaft is made of 4130 chromoly tubing and aircraft quality u-joints with sealed lubrication — made for car with those tight engine compartments or header clearances. The kit comes with the column tube (with self lubrication bushings), a splined adapter for Pinto-style racks, and all of the hardware needed for installation, including an SFI steering wheel disconnect.

In the beginning we were offering a lot of pre-welded kits that were more dedicated to the Rick Jones-built cars, but today, we focus on producing components that are more universal, to really reach the do-it-yourself racers. – Josh Dixon

The RJ Pro Series brake pedal (Part No. 980325) was installed using Quarter-Max’s brake line kit (Part No. 206112), that came with everything needed to plumb the brakes, including hard-line, fittings, brackets, and hose, and also included hose ends and plumbing for brake pressure gauges. The pedal fits on a one-inch shaft, and is paired with a custom throttle pedal that the PMR team made, which uses a dual return spring mechanism and a Morse-style throttle cable that leaves no slack whatsoever in the line, as some setups are prone to have. Also in direct contact with the driver — the parachute release mechanism — we used their Dual Parachute Cable kit, that comes with both lines needed to wire up the pair of parachutes we now have on the car. The kit comes with a single parachute lever for both chutes, which is mounted on the roof of the chassis within easy reach.

A new, low-profile VFN fiberglass nose was added to our EOM composite fenders, mated using bolts, to create a lightweight, one-piece, lift-off front end. To make the nose removable, we had to construct the the tree and bracketry to hold it in place. The team at PMR fabricated the forward portion of the tree and the brackets in-house, but turned to Quarter-Max and their Rear Front End Mount kit (Part No. 219605-1) for the rear mounting points, which allows you to mount the rear of a fiberglass or carbon front end (ours still used the factory composite quarters and an aftermarket fiberglass hood and nose) to the firewall and the front of the rocker panels. Quarter-Max constructs this kit from 4130 chromoly, and includes the quarter-turn ‘dzus’ fasteners and springs for mounting.

In this view, you can see the supporting structure in the chassis that PMR has fabricated to help protect the front of the car, including the supercharger, in the event of an impact.

PMR fabricated a forward crossmember that ties in the stock front framerail, to serve as both a protection point for the ProCharger, but also to serve as the basis for the front tree to mount and support the front end.

“On the left side and right side, we also incorporated some structural tubing in to mount the dry sump oil tank and the fuel cell on opposite sides,” Tony explained. This tubing not only serves as the mount for the oil and fuel tank, but is also a protection point, as both are situated outside of the framerails.

Here’s the new fiberglass nose that PMR fabricated mounting points and support structure for to mate with the stock composite fenders and fiberglass hood.

The PMR team mounted the nose in similar fashion to the way a full-tube, Pro Stock-style car would be set up, but because the nose is a three-piece-into-one product, they did have to incorporate some extra structural support into the tree to support the nose and allow it to keep its shape at speed. To create the tree, PMR welded bars to a steel plate that was then riveted to the front end and fiberglassed over, creating essentially a permanent bond. Once on the car, those support bars of the tree rest on specific points on the chassis.

And lastly, we’ve used a set of QM’s carbon fiber tube protectors to protect the finish of the chassis, particularly in the drivers compartment cross brace. A set of protectors in 1-5/8-inch and 1-1/4-inch diameters allows us to cover virtually any bar in the car.

Final Assembly

Once the transmission tunnel was complete (and the new floor back in the car), we installed new carpet to give the car a somewhat stock appearance inside. Showing are the dzus tabs that make for quick removal of the tunnel.

This brings us down to some of the final steps in the completion of BlownZ’s makeover — namely the re-installation of the floors, the suspension setup, wiring of the parachutes, and plumbing.

As we saw earlier, the stock floor was completely removed to make room for the construction of the chassis and, for a time, removal of the stock framerails. Said framerails are now back in the car and with the back half of the chassis complete, it was time to re-install the floor. As the NMCA WEST rules outline, we were allowed to use essentially a stock replacement floor in the cockpit area – made of steel and generally of the same thickness as the original floor, albeit cut and notched to fit around the tubular structure of the chassis. However, from the main hoop back, a fabricated sheet metal floor can be installed, and that’s exactly what the PMR team has done, as you can see.

Our dual Stroud parachutes installed at the recommended 45-degree angle, which helps them properly deploy into the airstream. The Quarter-Max mount keeps the chutes up and out from under the spoiler and separates them slightly for easier deployment and re-packing.

With that done, we could then begin some of the wiring, and specifically, for the parachutes. The single parachute lever has been mounted on the side of the roll cage, and the cables have been routed along the chassis out to the rear bumper, where they’re fed through to the parachutes themselves. As part of the Quarter-Max parachute kit that we received, the mounting brackets for the actual parachute lines are included, and with those already welded to the chassis, it was only a matter of putting the lines in place.

We’ve utilized Racecraft’s front and rear suspension packages on the car, along with their 9-inch rear end housing. Up front is their prefabbed K-member (which we mentioned earlier) that, according to Tony, took care of much of the suspension mounting points, including the lower control arm mounts and the rack and pinion box.

“They’ve done a great job with the bump steer and everything with it, so that was pretty well all worked out for us,” he explained. The upper mounts for the struts, also a kit from Racecraft specific to the F-body, required some minor modifications to the factory strut tower.

Here’s a look at the final rear end and suspension assembly, centered around the Racecraft housing and custom torque arm.

Out back, PMR stuck with a general set of specifications supplied by Racecraft for the lower trailing arms and the torque arm, both of which were made specific to the F-body. PMR fabricated a custom torque arm mount into the chassis, making it adjustable so it could be moved up or down to make it more or less aggressive. The shocks, likewise, use points already fabricated and set up by Racecraft. PMR was primarily tasked with creating an upper shock mount on the chassis for the shocks and the anti-roll bar, and mocked the rear end up at the desired ride height, and could from there dictate the proper mounting location for the shocks and weld on the mounts for the shocks and ARB.

This series of photos shows the Racecraft torque arm and the torque arm mount that PMR fabricated into the chassis, located near the center of the car.

Our front suspension, comprised of Racecraft's new K-member and lower control arms, along with Santhuff strut-style shocks.

Moving to the cockpit, all of the mounting brackets were installed for the intercooler, which unlike previously where it was mounted in what would’ve been the passenger seat, is now tucked up under the dash, mounted to the ‘knee’ bar, placing the intercooler less than 12 inches from the throttle body. This will provide us with what we hope is cooler, less turbulent air going into the engine.

We’ve intentionally positioned the new intercooler up underneath the dash to make it as close to the throttle body inlet as possible, which we hope will deliver cooler and less turbulent air into the engine. The tank is bolted to the “knee bar” of the chassis using a set of fabricated brackets.

Another of the final steps in the process, which we’ll be diving into as well in a future story, is the plumbing of the car, using an extensive lineup of hoses and fittings from Fragola Performance Systems for plumbing the fuel, oil, and water systems of the car. We utilized Fragola’s black anodized, aluminum Series 2000 and 3000 fittings throughout, to create a nice, clean look overall.

We utilized the full gamut of high quality hoses and Series 1000 and 2000 hose ends from Fragola -- in a black anodized finish -- throughout the plumbing of the car, including the fuel, water, and oiling systems.

With this work complete, we could finally put the wheels and tires on the car and drop it down on the floor for the first time and officially call it a rolling chassis. There is of course a lot of work yet to be done before we can make our debut, and in an upcoming follow-up story, we’ll get into all of the assembly carried out back out at the Power Automedia shop, as we wire and plumb the car and get it ready to hit the track. With just a few short weeks between receiving the car from PMR Race Cars and the NMCA WEST opener in Fontana, there was a lot to do in a short amount of time, so as you can imagine, the pressure was on.